Bugged colossus slayer and then take the martial adept feat at lvl 4 giving you access to menacing attack and you got a hell of an opening shot. But ofc that's min-maxing for lvl 4 which won't make sense in the full game (especially once we have sharpshooter to choose instead). I agree that the beastmaster spider is a larger balance issue than a colossus slayer once it's fixed. In divinity 2 you could do similar shenanigans with summons but enemies would heal after leaving combat, so without multiple summoners, it was impractical to suicide run in summon after summon. Summon beast needs to be changed to a once a day ability. This then gives some utility to beastmasters who also chose find familiar at lvl 1 in the event your main pet is slain. This is assuming that after long rest enemies also heal, I haven't actually tested that but they certainly should. Then available pet options need to be better balanced. Beastmaster already has a significant bonus in that the pet's initiative is it's own instead of requiring a bonus action from the ranger to command it to do something.
